SOLUTION: Use sum and difference identities to find the exact value of sin 15 degrees (two angles given are 45 degrees and 60 degrees.)

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Question 1098093: Use sum and difference identities to find the exact value of sin 15 degrees (two angles given are 45 degrees and 60 degrees.)
Found 3 solutions by Alan3354, ikleyn, MathTherapy:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Use sum and difference identities to find the exact value of sin 15 degrees (two angles given are 45 degrees and 60 degrees.)
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Good idea.
Look up sum and difference identities.
Wikipedia covers it well.
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Use either 60 & 45, or 45 & 30 degrees.
I could do it, but I think the practice will benefit you more than it would me.
Answer by ikleyn(52787)   (Show Source): You can put this solution on YOUR website!
.
See the lesson
    - Calculating trigonometric functions of angles, Problem 1
in this site.


Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

Use sum and difference identities to find the exact value of sin 15 degrees (two angles given are 45 degrees and 60 degrees.)
sin (A - B) = sin A cos B - cos A sin B

sin (60 - 45) = sin 60 cos 45 - cos 60 sin 45

If you don't know these ratios, you need to look them up on the UNIT CIRCLE chart! 

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